This invention relates to automatic accompanying apparatus in which the automatic accompaniment of a bass tone or chord tone complying with a chord name assigned by depressing a plurality of desired keys of an accompanying keyboard is effected. More particularly, it relates to a keyboard type automatic accompanying system which has a chord detector comprising a shift register and a read only memory (ROM) device in combination.
An automatic accompanying system of the type having a keyboard generates a chord tone or bass tone corresponding to a key depression state in such a way that key depression signals produced by the depression of a plurality of keys on an accompanying keyboard and the assignment of a chord name (such as C major and D minor) by a performer are processed in electronic circuitry. Such an automatic accompanying apparatus requires a chord detector which detects the chord name defined by the depressed accompanying keys.
In this respect, the number of key depression states which are assigned by the performer is very large. As the number of chord types to be detected increases, the circuit arrangement inevitably becomes complicated. Even when the number of chord types to be detected is constant, the degree of complexity of the circuit arrangement varies greatly depending on what chord detection system is adopted.
For these reasons, there is employed a chord detector for which the number of chord types to be detected is made as small as possible and which detects only principal chords of high frequency of use as are musically important, for example, only major, minor, seventh etc. From the side of the performer, however, a smooth performance needs to be made even in case where any chord other than the principal chords has been assigned.
Further, apparatus of still higher grades have such various functions that a chord and a bass tone are automatically played in rhythmic accompaniment merely by depressing a single key on an accompanying keyboard and that an automatic accompaniment is effected by a chord played on an accompanying keyboard and a bass tone adequate thereto.
Although a variety of chord detection systems have heretofore been proposed, they are not always fully satisfactory from the viewpoints of simplification of the circuit arrangement, adaptability to the form of an LSI, various requests in performance from the side of a performer, etc.